Soccer is a complex sport, and balance appears to play a crucial role in the quality execution of technical skills, which are mostly performed while standing on one foot. Nevertheless, in younger ages, when learning still affects soccer performance, the effect of a balance-training program on the player’s balance and technical skills remains unexplored. This research examined the effect of a balance-training program (BTP) on balance and technical skills of adolescent soccer players. Τhe participating volunteers were thirty-two soccer players (12-13 years old with 3.84 ± 0.95 years of practice), randomly separated into two groups: an experimental (EXP, n1 = 17) and a control group (CON, n2 = 15). Both groups were evaluated in static and dynamic balance and in technical skills (dribbling, passing, juggling, and shooting with dominant and non-dominant legs) before (Pre-condition) and after the intervention (Post-condition) which was an eight-week BTP for the EXP group and a placebo-training program for the CON group. Α 2 by 2 (groups×condition) mixed analysis of variance (ANOVA) with repeated measures on the condition factor was used to assess possible differences between groups. A significant groups × condition interaction effect was found in dynamic balance (p = 0.008), static (p = 0.042), and shooting (p = 0.022) with dominant leg performance. The EXP group improved (p = 0.007) its static balance by 37.82% and also significantly improved its dynamic balance and shooting accuracy with dominant leg in Post condition by 24.98% (p = 0.006) and 83.84% (p = 0.006) respectively. No significant improvement of other variables was detected in the EXP group Post condition. Dynamic and static balance, and shooting with dominant leg skills can be improved in adolescent soccer players through a specialized 8-week BTP. Balance-training program may contribute to technical skill improvement in soccer training.

Jumping ability in basketball is usually assessed using standardized vertical jump tests. However, they lack specificity and do not consider the player’s basketball skills. Several studies have suggested performing specific jump tests, which are tailored to the movement patterns and requirements of a basketball game. The pivot step jump test (PSJT) is a novel test designed to evaluate the specific jumping abilities of basketball players by combining a pivot step on one leg with a maximum bilateral vertical jump. This study had two aims: to determine the reliability and validity of the PSJT using typical jump tests as the criterion measure and to demonstrate the PSJT as a practical test to evaluate specific jumping ability in young male and female basketball players. Twenty female (EGA; 14.0 ± 0.7 years, 59.3 ± 7.9 kg, 162.1 ± 5.5 cm) and fifteen male (EGB; 14.0 ± 0.7 years, 58.1 ± 7.7 kg, 170.3 ± 6.4 cm) basketball players participated in the study. The test–retest reliability of the PSJT within sessions (intrasession reliability) and across sessions (intersession reliability) was assessed within EGA. For the evaluation of validity, EGB performed the PSJT and a series of criterion jumping tests. For EGA, no changes (p > 0.05) were found in PSJT performance between test sessions and excellent intra- and intersession reliability was observed (ICCs > 0.75). Correlation coefficients indicated high factorial validity between the jumping tests and PSJT (r = 0.71–0.91, p < 0.001). The PSJT appears to offer a valid assessment of jumping ability in basketball and is a practical test for assessing sport-specific jumping skills in young basketball players.

The purpose of this study was to examine the effect of a soccer small-sided game (SSG) on performance, inflammatory, muscle damage and hormonal indicators. Twenty-two male soccer players participated and were assigned to either experimental (EXP = 12) or control (CON = 10) groups. Subjective fatigue (RPE) and lactate (La¯) were measured during the SSG; vertical squat jump (SJ), 20-m sprint, creatine kinase (CK), interleukin-6 (IL-6), cortisol (C), and testosterone (T) were measured before (PRE), after (POST), 24 h, 48 h, and 72 h after the SSG in the EXP group. The heart rate during the SSG reached 92 ± 3% of their HRmax, whereas La¯ and RPE reached 13.02 ± 1.60 mmol·L⁻¹ and 15 ± 1 after SSG, respectively. The IL-6, different among measurements (F (1.04, 11.50) = 504.82, p < 0.001), peaked (3.52 ± 0.43 pg·mL⁻¹ [95%CI; 3.28–3.77]) after the SSG and returned to baseline 24 h later. The CK, different among measurements (F (1.76, 19.32) = 93.96, p < 0.001), peaked (536.58 ± 124.73U·L⁻¹ [95%CI; 466.01–607.15]) 24 h after the SSG and remained significantly higher than PRE condition in POST and up to 72 h later. The T/C ratio, significantly different among measurements (F (1.73, 19.05) = 12.12, p < 0.001), was at its lowest (0.44 ± 0.16 [95%CI; 0.35–0.54]) immediately after the SSG (p < 0.05) and returned to baseline after 24 h. It seems that 48 h (at the most) after an SSG is adequate time for players to recover, and a high training load should be avoided sooner than 24 h after an SSG.

Objectives: This study examined physiological, biochemical, and performance adaptations in 18 semi-professional male soccer players across three seasonal phases: pre-season initiation (PS), pre-competition (PC), and mid-season (MS). Methods: Assessments included physical/performance/hormonal/biochemical markers. Results: From PS to PC, body fat (Cohen’s d = −0.88; p ≤ 0.01) and speed drop rate (Cohen’s d = −1.52; p ≤ 0.01) significantly decreased, while V̇O₂max (Cohen’s d = 0.80; p ≤ 0.01), velocity at V̇O₂max (Cohen’s d = 1.86; p ≤ 0.01), and velocity at the second ventilatory threshold (Cohen’s d = 1.54; p ≤ 0.01) significantly increased. Significant fluctuations were observed in creatine kinase (Cohen’s d = 4.34; p ≤ 0.01), myoglobin (Cohen’s d = 0.66; p ≤ 0.01), and cortisol (Cohen’s d = −1.14; p ≤ 0.01) levels. From PS to MS, further reductions in body fat (Cohen’s d = −0.81; p ≤ 0.01) and speed drop rate (Cohen’s d = −1.12; p ≤ 0.01) were observed, along with significant improvements in countermovement jump performance (Cohen’s d = 1.08; p ≤ 0.01) and cardiorespiratory fitness (Cohen’s d ≥ 0.83; p ≤ 0.01). Creatine kinase (Cohen’s d = 3.82; p ≤ 0.01), myoglobin (Cohen’s d = 1.50; p ≤ 0.01), interleukin-6 (Cohen’s d = 1.24; p ≤ 0.01), and testosterone (Cohen’s d = 0.92; p ≤ 0.01) significantly increased. Stability in lower limb strength, flexibility, triglycerides, C-reactive protein, ferritin, liver enzymes, and most hematological parameters suggest resilience to seasonal demands. Conclusions: Seasonal training enhanced fitness and hormonal balance while maintaining physiological stability. These findings underscore the importance of periodized training to manage muscle damage and sustain an anabolic hormonal profile for peak performance. Consistent diet and training support metabolic health, while tailored recovery strategies and season-specific interventions are essential for optimizing performance and minimizing injury risk.